Ghost Curse would be a pretty useless attack in competitive battling.
Assuming your opponent can switch, they'll simply do so, and you've cut your HP in half for nothing. Assuming you've Mean Looked them or something, well, 1/4 damage isn't really a lot, and they'll probably kill you before they die of the Curse.
Assuming your opponent can switch, they'll simply do so, and you've cut your HP in half for nothing. Assuming you've Mean Looked them or something, well, 1/4 damage isn't really a lot, and they'll probably kill you before they die of the Curse.